The present invention relates to a headset for a bicycle, and more particularly to a headset which has an upper bearing assembly and a lower bearing assembly each bearing having a plurality of rollers disposed in an inclined fashion therein and the inclined angle regarding to a vertical line of the rollers is 10-20 degrees for the upper bearing assembly and 45 degrees for the lower bearing assembly respectively.
Referring to FIG. 1, a conventional headset of a bicycle generally includes an upper bearing assembly 50 and a lower bearing assembly 60 between which a head tube 70 is disposed. A steerer tube 80 is inserted from the lower bearing assembly 60 via the head tube 70 to the upper bearing assembly 50 and is threaded engaged to an adjusting nut 51 disposed on a top of the upper bearing assembly 50 such that the steerer tube 80 is rotatably engaged between the upper and lower bearing assemblies 50, 60. Each bearing assembly has a first race 501 or 601 and a second race 502 or 602 which respectively abut a first bowl 52 or 61 and a second bowl 53 or 62. A bearing 503 or 603 is securely engaged between the first and second races 501, 502 or 601, 602, generally, the bearings 503, 603 are disposed by the same inclined angle of 45 degrees regarding to a vertical line of respective assembly 50, 60. The upper and lower bearing assemblies 50, 60 require different installing standards, namely, the upper bearing assembly 50 requires less rotating feature than the lower bearing assembly 60 because the lower bearing assembly 60 is designed for providing a smoothly rotating feature for the steerer tube 80, however, the upper bearing assembly 50 is required to hold and maintain the head tube and the two assemblies 50, 60 in place rather than to provide a smoothly rotating feature. Therefore, because of the similarity in design of the two bearings 503, 603, when an assembler rotates the adjusting nut 51, a vertical component force will transfer to the lower bearing 603 and the larger the vertical component force is produced the less rotating feature of the lower bearing 603 performs, and the larger the angle of the bearing disposed regarding to the vertical line the larger the vertical component force will be produced, this is opposite to the principle of the features required of the bearings 503, 603 mentioned above. Should the lower bearing 603 rotate unsatisfactorily, the assembler must loosen both the upper and lower bearing assemblies 50, 60 and re-check them again.
The present invention intends to provide a headset where the upper bearing has a plurality of rollers disposed therein in an inclined fashion, the inclined angle is 10-20 degrees regarding to a vertical line and by which a less vertical component force will be produced when assembling the upper bearing assembly therefore mitigating and/or obviating the above-mentioned problems.